One of the pioneers of the S.F. craft beer scene, ThirstyBear Organic Brewery puts out a limited-edition Stave Series ever year. (Last year’s effort was an imperial porter aged in bourbon barrels called The Dark Age.) For 2016, the SoMa brewers looked to Belgium and to California’s Wild West history to create Stave Series No. 16: The Wild American.

Initially fermented with the wild yeast Bruxellensis Trois and dry-hopped with Mosaic (a variety of American hops), it’s inoculated with the funkier yeast known as Brettanomyces (“Brett”) for a secondary fermentation and aged for nine months in the same barrels used for The Dark Age. Complicated? Maybe. But head brewmaster and certified cicerone Brenden Dobel calls the tart golden ale that results a “nod to the American craft brewer’s love of the hop,” owing to its mango and pineapple notes.

At six percent ABV and 25 IBU, The Wild American is highly drinkable, a smooth ale with a bit of pucker. And it’s available only on tap at ThirstyBear, San Francisco’s longest-operating brewery-restaurant (which celebrated its 20th anniversary in September).